1. Field of the Invention
This invention relates to a dew formation prediction method and apparatus, and an environment air temperature estimating method and apparatus, which may conveniently be used for estimating the environment air temperature by a temperature sensor provided in an electronic equipment and for predicting the dew formation on an object under measurement provided in the electronic equipment.
2. Description of Related Art
If, in an object under measurement, such as a drum, of a tape transport system of a helical scanning system, provided in an electronic equipment, such as a data recorder or a video tape recorder, dew is produced, the magnetic tape may stick to the drum and thereby is unable to run, while there is a risk of the magnetic tape being damaged seriously.
Up to now, a dew formation sensor is provided for this drum and, when the dew formation is detected by this dew formation sensor, air is blown onto this drum by e.g., an air blowing fan, whilst the apparatus is allowed to stand until the dew drops have disappeared.
Meanwhile, the conventional dew formation sensor checks the dew formation based on changes in the resistance of the due formation sensor. However, changes in the resistance in the vicinity of the dew point temperature are extremely small so that it is difficult to verify whether or not the dew formation has actually occurred.
When a data recorder is used outdoors to record measurement data on magnetic tape using a tape transport system with the helical scan system and then brought indoors to reproduce the measurement data, there are cases where dew drops are formed on the drum surface but the change in resistance of the due formation sensor is so small that the sensor falls to respond to that change, giving an incorrect decision.
For eliminating such mistaken decisions, it is necessary to approximate the ambient environment of the dew sensor to that of the drum. In particular, in an electronic equipment in which forced convection is used for heat dissipation, limitations are placed on the mounting position of the dew formation sensor.
Moreover, in order for the dew formation sensor to detect the dew formation on the drum reliably, the thermal capacity of the dew formation sensor needs to be equal to that of the drum, such that a sufficient space is required around the dew formation sensor and hence the space saving demand is not met.
It is therefore an object of the present invention to provide a method and apparatus for detecting the temperature of the environment air around the electronic equipment and an object under measurement mounted in the electronic equipment to predict dew formation satisfactorily.
In one aspect, the present invention provides a dew formation prediction apparatus including object temperature detection means for detecting the temperature of an object provided in an electronic equipment, environment air temperature acquiring means for acquiring the environment air temperature surrounding the electronic equipment, dew point temperature calculating means for calculating the dew point temperature at a humidity which takes the operating environment around the electronic equipment into account, from the environment air temperature, and dew formation occurrence verification means for verifying the occurrence of dew formation when the temperature of the object as acquired by the object temperature detection means is not higher than the dew point temperature.
In another aspect, the present invention provides a dew formation prediction method including detecting the temperature of an object provided in an electronic equipment, acquiring the environment air temperature of the electronic equipment, calculating the dew point temperature at a humidity which takes the operating environment around the electronic equipment into account, from the environment air temperature, and verifying the occurrence of dew formation when the temperature of the object is not higher than the dew point temperature.
In still another aspect, the present invention provides an environment air temperature estimating apparatus including temperature measurement means for measuring the temperature T0 on powerup of an object under measurement provided in an electronic equipment and the temperature T1 of the object under measurement after lapse of a pre-set time as from powerup and environment air temperature calculating means for calculating the environment air temperature TE from
TE=AT1xe2x88x92BT0xe2x88x92C
where T0 is the temperature on powerup of the object under measurement as obtained by the object temperature measurement means, T1 is the temperature of the object under measurement after lapse of a specified time period as from powerup, A and B are coefficients to compensate for the variations in the ambient environment inside and outside the electronic equipment and C is a constant representing the environment air temperature TE when AT1 and BT0 representing the temperatures of the object under measurement when taking into account the conditions of the environment inside and outside the electronic equipment are equal to each other.
In still another aspect, the present invention provides an environment air temperature estimating method including measuring the temperature T0 on powerup of an object under measurement provided in an electronic equipment and the temperature T1 of the object under measurement after lapse of a pre-set time as from the and calculating the environment air temperature TE from
TE=AT1xe2x88x92BT0xe2x88x92C
where T0 is the temperature as measured on powerup of the object under measurement, T1 is the temperature of the object under measurement after lapse of a specified time period as from powerup, A, B are coefficients to compensate for the variations in the conditions of the ambient environment inside and outside the electronic equipment and C is a constant representing the environment air temperature TE when AT1 and BT0 representing the temperatures of the object under measurement when taking into account the conditions of the environment inside and outside the electronic equipment are equal to each other.
In yet another aspect, the present invention provides a recording and/or reproducing apparatus of a helical scan system having a tape transport system, including drum temperature detection means for detecting the temperature of a drum of the tape transport system provided in a main body of the apparatus, environment air acquisition means for acquiring the environment air temperature around the main body of the apparatus, dew point temperature calculating means for calculating, from the environment air temperature, the dew point temperature at a humidity which takes into account the operating temperature around the main body of the apparatus, and dew formation occurrence verification means for verifying the occurrence of dew formation when the drum temperature as obtained by the drum temperature detection means is not higher than the dew point temperature.
According to the present invention, detection of the temperature of an object set in an electronic equipment and estimation of the environment air temperature around the electronic equipment can be achieved using a sole temperature sensor to enable dew formation to be predicted satisfactorily.
That is, according to the present invention, the environment air temperature can be estimated by providing a sole temperature sensor adapted to measure the temperature of an object provided in the electronic equipment. The measured results can be used to predict the dew formation satisfactorily.
Moreover, according to the present invention, since a sole temperature sensor is provided in the electronic equipment for measuring the object temperature, there is no risk of wastefully consuming the space available in the electronic equipment.